1. Field of the Invention
The present invention relates generally to devices for handling containers designed for liquid sample collection and for presenting such containers to clinical analyzers.
2. Description of the Prior Art
The sampling of fluids for diagnostic or evidentiary purposes is very common. Such fluids, which include urine, blood, water, milk etc., are collected in a specimen container and transported to a laboratory where they are analyzed to determine the presence of infections or contaminants such as drugs, alcohol etc. Under such circumstances, the collected sample must be maintained uncontaminated until the various testing procedures have been concluded. Containers for this purpose are common and usually comprise a plastic container having a secure lid.
Upon arrival at the testing laboratory, portions of the sample are manually, semi-automatically or automatically removed from the sample collection container into a secondary container, usually a disposable plastic test tube. In the manual case, the sample is "aliquotted" by pouring the liquid from the collection container. In the semi-automatic case, the sample container is opened and a portion of the sample is removed by lowering a pipette tip into the liquid and extracting the desired volume. In the automatic case, the lid is either removed or punctured by the apparatus and a pipette tip is lowered into the sample for extracting the desired volume.
Since the collected sample may pose a biohazard risk, great care must be taken to ensure that the liquid sample is not spilled during the handling of the container or the extraction of the sample aliquot. For this reason, a fully automatic system for handling the sample container is preferred.
Another problem associated with the known methods lies in the aliquot extraction step using pipettes. For example, the pipettes must be disposable for high throughput and reduced contamination risk. This leads to high levels of waste and a run-time cost for the system. Further, pipette tips are very difficult to change while a fully automated system is running. In a manual or semi-automatic system, there is direct contact with the liquid and, therefore, a contamination risk.
Other disadvantages with known fully automated systems lies in designing the required apparatus for removing the caps of the sample containers. Further, the tamper resistant seals, which are used to ensure that contamination of a sample has not occurred, are difficult to remove in automated systems.
One proposed automated system and apparatus for handling sample containers is taught in U.S. Pat. No. 5,549,141. This patent teaches an apparatus designed for a particular sample container which removes the need for manual handling.
A liquid sample container which provides safe use is taught in U.S. application Ser. No. 08/879,301 (which is incorporated herein by reference). The container described in U.S. application Ser. No. 08/879,301 includes a cap which is specifically designed for dispensing an aliquot of liquid and which is also designed for a fully automated system. However, no apparatus in known which is capable of utilizing such a container.
The present invention seeks to provide a process and apparatus for removing an aliquot from the above mentioned container and to convey such aliquot to the required clinical analyzers.